// Reusable HMAC-SHA256 Webhook Verification Utility
// All webhook handlers call WebhookVerifier.verify(req)
public class WebhookVerifier {
    public static Boolean verify(RestRequest req) {
        String signature =
            req.headers.get('X-MailOdds-Signature');
        String secret = MailOdds_Config__c.getOrgDefaults()
            .Webhook_Secret__c;
        if (String.isBlank(signature)
            || String.isBlank(secret)) return false;

        Blob expectedMac = Crypto.generateMac(
            'HmacSHA256',
            req.requestBody,
            Blob.valueOf(secret)
        );
        String expected =
            EncodingUtil.convertToHex(expectedMac);
        return constantTimeEquals(signature, expected);
    }

    // Prevent timing attacks
    private static Boolean constantTimeEquals(
        String a, String b
    ) {
        if (a.length() != b.length()) return false;
        Integer diff = 0;
        for (Integer i = 0; i < a.length(); i++) {
            diff |= a.charAt(i) ^ b.charAt(i);
        }
        return diff == 0;
    }
}

// Apex: Send Transactional Email via Named Credential
public class MailOddsSendService {
    @future(callout=true)
    public static void sendEmail(
        String toEmail, String subject,
        String htmlBody, String domainId
    ) {
        try {
            HttpRequest req = new HttpRequest();
            req.setEndpoint(
                'callout:MailOdds/v1/deliver');
            req.setMethod('POST');
            req.setHeader('Content-Type',
                'application/json');
            req.setTimeout(120000);

            Map<String, Object> body =
                new Map<String, Object>{
                    'to' => new List<Map<String, String>>{
                        new Map<String, String>{
                            'email' => toEmail
                        }
                    },
                    'from' => 'notifications@'
                        + getDomainName(domainId),
                    'domain_id' => domainId,
                    'subject' => subject,
                    'html' => htmlBody,
                    'tags' => new List<String>{
                        'salesforce-triggered'
                    },
                    'track_opens' => true,
                    'track_clicks' => true,
                    'options' => new Map<String, Object>{
                        'validate_first' => true
                    }
                };
            req.setBody(JSON.serialize(body));

            HttpResponse res = new Http().send(req);
            if (res.getStatusCode() == 200) {
                Map<String, Object> result =
                    (Map<String, Object>)
                    JSON.deserializeUntyped(
                        res.getBody());
                // Store result.message_id for
                // engagement tracking via
                // GET /v1/message-events
            }
        } catch (Exception ex) {
            System.debug(LoggingLevel.ERROR,
                'SendEmail error: ' + ex.getMessage());
        }
    }

    private static String getDomainName(String id) {
        Sending_Domain_Config__mdt cfg = [
            SELECT Domain_Name__c
            FROM Sending_Domain_Config__mdt
            WHERE Domain_Id__c = :id LIMIT 1
        ];
        return cfg?.Domain_Name__c ?? 'mail.example.com';
    }
}

// Apex: Batch Deliver to Campaign Members (max 100)
public class BatchDeliverService {
    @future(callout=true)
    public static void sendToCampaignMembers(
        Id campaignId, String domainId,
        String subject, String htmlBody
    ) {
        try {
            List<CampaignMember> members = [
                SELECT Contact.Email, Contact.Name,
                    Lead.Email, Lead.Name
                FROM CampaignMember
                WHERE CampaignId = :campaignId
                LIMIT 100
            ];

            List<Map<String, String>> recipients =
                new List<Map<String, String>>();
            for (CampaignMember cm : members) {
                String email = cm.Contact?.Email != null
                    ? cm.Contact.Email : cm.Lead?.Email;
                String name = cm.Contact?.Name != null
                    ? cm.Contact.Name : cm.Lead?.Name;
                if (email == null) continue;
                recipients.add(new Map<String, String>{
                    'email' => email,
                    'name' => name
                });
            }

            HttpRequest req = new HttpRequest();
            req.setEndpoint(
                'callout:MailOdds/v1/deliver/batch');
            req.setMethod('POST');
            req.setHeader('Content-Type',
                'application/json');
            req.setTimeout(120000);
            req.setBody(JSON.serialize(
                new Map<String, Object>{
                    'to' => recipients,
                    'from' => 'campaigns@'
                        + getDomainName(domainId),
                    'domain_id' => domainId,
                    'subject' => subject,
                    'html' => htmlBody,
                    'track_opens' => true,
                    'track_clicks' => true
                }
            ));

            HttpResponse res = new Http().send(req);
            // 202 Accepted: batch queued for delivery
        } catch (Exception ex) {
            System.debug(LoggingLevel.ERROR,
                'BatchDeliver error: ' + ex.getMessage());
        }
    }

    private static String getDomainName(String id) {
        Sending_Domain_Config__mdt cfg = [
            SELECT Domain_Name__c
            FROM Sending_Domain_Config__mdt
            WHERE Domain_Id__c = :id LIMIT 1
        ];
        return cfg?.Domain_Name__c ?? 'mail.example.com';
    }
}

// Apex: Create and Send MailOdds Campaign from SF
public class CampaignSendService {
    @future(callout=true)
    public static void createAndSendCampaign(
        Id sfCampaignId, String listId,
        String domainId
    ) {
        try {
            Campaign camp = [
                SELECT Name, Description
                FROM Campaign WHERE Id = :sfCampaignId
                LIMIT 1
            ];

            // 1. Create campaign
            HttpRequest createReq = new HttpRequest();
            createReq.setEndpoint(
                'callout:MailOdds/v1/campaigns');
            createReq.setMethod('POST');
            createReq.setHeader('Content-Type',
                'application/json');
            createReq.setTimeout(15000);
            createReq.setBody(JSON.serialize(
                new Map<String, Object>{
                    'name' => camp.Name,
                    'list_id' => listId,
                    'domain_id' => domainId
                }
            ));
            HttpResponse createRes =
                new Http().send(createReq);
            if (createRes.getStatusCode() != 201) return;

            Map<String, Object> result =
                (Map<String, Object>)
                JSON.deserializeUntyped(
                    createRes.getBody());
            Map<String, Object> campaign =
                (Map<String, Object>)
                result.get('campaign');
            String campaignId =
                (String) campaign.get('id');

            // 2. Add A/B variant
            HttpRequest varReq = new HttpRequest();
            varReq.setEndpoint(
                'callout:MailOdds/v1/campaigns/'
                + campaignId + '/variants');
            varReq.setMethod('POST');
            varReq.setHeader('Content-Type',
                'application/json');
            varReq.setTimeout(10000);
            varReq.setBody(JSON.serialize(
                new Map<String, Object>{
                    'subject' => camp.Name,
                    'html' => '<h1>' + camp.Name + '</h1>'
                        + '<p>' + camp.Description + '</p>',
                    'weight' => 100
                }
            ));
            new Http().send(varReq);

            // 3. Send campaign
            HttpRequest sendReq = new HttpRequest();
            sendReq.setEndpoint(
                'callout:MailOdds/v1/campaigns/'
                + campaignId + '/send');
            sendReq.setMethod('POST');
            sendReq.setTimeout(15000);
            new Http().send(sendReq);
        } catch (Exception ex) {
            System.debug(LoggingLevel.ERROR,
                'CampaignSend error: '
                + ex.getMessage());
        }
    }
}

// Apex: Fetch Sender Health + Trend for LWC Dashboard
public with sharing class SenderHealthController {
    @AuraEnabled(cacheable=true)
    public static Map<String, Object> getSenderHealth() {
        HttpRequest req = new HttpRequest();
        req.setEndpoint(
            'callout:MailOdds/v1/sender-health');
        req.setMethod('GET');
        req.setTimeout(10000);
        HttpResponse res = new Http().send(req);
        if (res.getStatusCode() != 200) {
            throw new AuraHandledException(
                'API returned ' + res.getStatusCode());
        }
        return (Map<String, Object>)
            JSON.deserializeUntyped(res.getBody());
    }

    @AuraEnabled(cacheable=true)
    public static Map<String, Object>
        getSenderHealthTrend(String period) {
        HttpRequest req = new HttpRequest();
        req.setEndpoint(
            'callout:MailOdds/v1/sender-health/trend'
            + '?period=' + (period ?? '30d'));
        req.setMethod('GET');
        req.setTimeout(10000);
        HttpResponse res = new Http().send(req);
        if (res.getStatusCode() != 200) {
            throw new AuraHandledException(
                'API returned ' + res.getStatusCode());
        }
        // Returns: period, data_points array with
        // daily score, grade, delivery_rate, bounce_rate
        return (Map<String, Object>)
            JSON.deserializeUntyped(res.getBody());
    }

    @AuraEnabled(cacheable=true)
    public static Map<String, Object>
        getSendingStats(String period) {
        HttpRequest req = new HttpRequest();
        req.setEndpoint(
            'callout:MailOdds/v1/sending-stats'
            + '?period=' + (period ?? '7d'));
        req.setMethod('GET');
        req.setTimeout(10000);
        HttpResponse res = new Http().send(req);
        if (res.getStatusCode() != 200) {
            throw new AuraHandledException(
                'API returned ' + res.getStatusCode());
        }
        // Returns: stats.sent, delivered, bounced,
        // open_rate, click_rate, complaint_rate
        return (Map<String, Object>)
            JSON.deserializeUntyped(res.getBody());
    }
}

// Apex: Full DMARC Suite from Salesforce
public class MailOddsDmarcService {
    // Register a domain for DMARC monitoring
    @future(callout=true)
    public static void registerDomain(String domain) {
        try {
            HttpRequest req = new HttpRequest();
            req.setEndpoint(
                'callout:MailOdds/v1/dmarc-domains');
            req.setMethod('POST');
            req.setHeader('Content-Type',
                'application/json');
            req.setTimeout(10000);
            req.setBody(JSON.serialize(
                new Map<String, String>{
                    'domain' => domain
                }
            ));
            HttpResponse res = new Http().send(req);
            if (res.getStatusCode() == 201) {
                Map<String, Object> data =
                    (Map<String, Object>)
                    JSON.deserializeUntyped(
                        res.getBody());
                // Store domain_id for verify/sources/trend
            }
        } catch (Exception ex) {
            System.debug(LoggingLevel.ERROR,
                'DMARC register error: '
                + ex.getMessage());
        }
    }

    // Verify DMARC DNS records are configured
    @future(callout=true)
    public static void verifyDomain(String domainId) {
        try {
            HttpRequest req = new HttpRequest();
            req.setEndpoint(
                'callout:MailOdds/v1/dmarc-domains/'
                + domainId + '/verify');
            req.setMethod('POST');
            req.setTimeout(10000);
            new Http().send(req);
        } catch (Exception ex) {
            System.debug(LoggingLevel.ERROR,
                'DMARC verify error: '
                + ex.getMessage());
        }
    }

    // Scheduled: check DMARC trend and alert on failures
    @future(callout=true)
    @TestVisible
    public static void checkDmarcHealth(
        String domainId
    ) {
        try {
            // 1. Get trend data
            HttpRequest trendReq = new HttpRequest();
            trendReq.setEndpoint(
                'callout:MailOdds/v1/dmarc-domains/'
                + domainId + '/trend?days=7');
            trendReq.setMethod('GET');
            trendReq.setTimeout(10000);
            HttpResponse trendRes =
                new Http().send(trendReq);

            // 2. Get policy recommendation
            HttpRequest recReq = new HttpRequest();
            recReq.setEndpoint(
                'callout:MailOdds/v1/dmarc-domains/'
                + domainId + '/recommendation');
            recReq.setMethod('GET');
            recReq.setTimeout(10000);
            HttpResponse recRes =
                new Http().send(recReq);

            // 3. Get sending sources
            HttpRequest srcReq = new HttpRequest();
            srcReq.setEndpoint(
                'callout:MailOdds/v1/dmarc-domains/'
                + domainId + '/sources?days=7');
            srcReq.setMethod('GET');
            srcReq.setTimeout(10000);
            HttpResponse srcRes =
                new Http().send(srcReq);

            // Aggregate findings into Task
            if (trendRes.getStatusCode() == 200) {
                Map<String, Object> trend =
                    (Map<String, Object>)
                    JSON.deserializeUntyped(
                        trendRes.getBody());
                List<Object> points =
                    (List<Object>) trend.get(
                        'data_points');
                // Check last 7 days for failures
                if (points != null
                    && !points.isEmpty()) {
                    Map<String, Object> latest =
                        (Map<String, Object>)
                        points[points.size() - 1];
                    Integer failCount =
                        (Integer) latest.get(
                            'fail_count');
                    if (failCount > 0) {
                        insert new Task(
                            Subject = 'DMARC failures '
                                + 'detected ('
                                + failCount + ' in 7d)',
                            Description =
                                'Trend: '
                                + trendRes.getBody()
                                    .left(2000)
                                + '\nSources: '
                                + srcRes.getBody()
                                    .left(2000)
                                + '\nRecommendation: '
                                + recRes.getBody()
                                    .left(1000),
                            Priority = 'High',
                            ActivityDate = Date.today()
                        );
                    }
                }
            }
        } catch (Exception ex) {
            System.debug(LoggingLevel.ERROR,
                'DMARC health check error: '
                + ex.getMessage());
        }
    }
}

// Apex: Cross-Reference Bounces with Contacts
public class MailOddsBounceSync {
    @future(callout=true)
    public static void syncBounces() {
        try {
            HttpRequest req = new HttpRequest();
            req.setEndpoint(
                'callout:MailOdds/v1/bounce-analyses');
            req.setMethod('GET');
            req.setTimeout(15000);
            HttpResponse res = new Http().send(req);
            if (res.getStatusCode() != 200) return;

            Map<String, Object> data =
                (Map<String, Object>)
                JSON.deserializeUntyped(res.getBody());
            List<Object> analyses =
                (List<Object>) data.get('analyses');
            Set<String> bouncedEmails =
                new Set<String>();

            for (Object a : analyses) {
                Map<String, Object> analysis =
                    (Map<String, Object>) a;
                // Fetch bounce records for each analysis
                String analysisId =
                    (String) analysis.get('id');
                HttpRequest recReq = new HttpRequest();
                recReq.setEndpoint(
                    'callout:MailOdds/v1/bounce-analyses/'
                    + analysisId + '/records');
                recReq.setMethod('GET');
                recReq.setTimeout(10000);
                HttpResponse recRes =
                    new Http().send(recReq);
                if (recRes.getStatusCode() != 200)
                    continue;

                Map<String, Object> recData =
                    (Map<String, Object>)
                    JSON.deserializeUntyped(
                        recRes.getBody());
                List<Object> records =
                    (List<Object>) recData.get(
                        'records');
                for (Object r : records) {
                    Map<String, Object> rec =
                        (Map<String, Object>) r;
                    bouncedEmails.add(
                        (String) rec.get('email'));
                }
            }

            if (bouncedEmails.isEmpty()) return;

            List<Contact> contacts = [
                SELECT Id, Email FROM Contact
                WHERE Email IN :bouncedEmails
            ];
            for (Contact c : contacts) {
                c.MailOdds_Bounce_Status__c = 'Bounced';
                c.MailOdds_Bounce_Synced_At__c =
                    Datetime.now();
            }
            update contacts;
        } catch (Exception ex) {
            System.debug(LoggingLevel.ERROR,
                'BounceSync error: ' + ex.getMessage());
        }
    }
}

// Apex: Fetch Suppression Stats for Dashboard
public with sharing class SuppressionStatsController {
    @AuraEnabled(cacheable=true)
    public static Map<String, Object>
        getSuppressionStats() {
        HttpRequest req = new HttpRequest();
        req.setEndpoint(
            'callout:MailOdds/v1/suppression/stats');
        req.setMethod('GET');
        req.setTimeout(10000);
        HttpResponse res = new Http().send(req);
        if (res.getStatusCode() != 200) {
            throw new AuraHandledException(
                'API returned ' + res.getStatusCode());
        }
        // Returns: total_entries, by_type breakdown,
        // recent additions
        return (Map<String, Object>)
            JSON.deserializeUntyped(res.getBody());
    }
}

// Apex: Identify Inactive Contacts for Re-Engagement
public class InactiveContactReportService {
    @future(callout=true)
    public static void findInactiveContacts(
        Integer inactiveDays
    ) {
        try {
            HttpRequest req = new HttpRequest();
            req.setEndpoint(
                'callout:MailOdds/v1/contacts'
                + '/inactive-report?days='
                + inactiveDays);
            req.setMethod('GET');
            req.setTimeout(15000);
            HttpResponse res = new Http().send(req);
            if (res.getStatusCode() != 200) return;

            Map<String, Object> data =
                (Map<String, Object>)
                JSON.deserializeUntyped(res.getBody());
            List<Object> inactive =
                (List<Object>) data.get('contacts');
            if (inactive == null
                || inactive.isEmpty()) return;

            Set<String> emails = new Set<String>();
            for (Object c : inactive) {
                Map<String, Object> contact =
                    (Map<String, Object>) c;
                emails.add(
                    (String) contact.get('email'));
            }

            // Flag matching Salesforce Contacts
            List<Contact> sfContacts = [
                SELECT Id, Email FROM Contact
                WHERE Email IN :emails
            ];
            List<Task> tasks = new List<Task>();
            for (Contact c : sfContacts) {
                c.Engagement_Status__c = 'Inactive';
                tasks.add(new Task(
                    WhoId = c.Id,
                    Subject = 'Re-engage: No activity '
                        + 'in ' + inactiveDays + ' days',
                    Priority = 'Normal',
                    ActivityDate = Date.today().addDays(7)
                ));
            }
            update sfContacts;
            if (!tasks.isEmpty()) insert tasks;
        } catch (Exception ex) {
            System.debug(LoggingLevel.ERROR,
                'InactiveReport error: '
                + ex.getMessage());
        }
    }
}